1.split文本转数组

  1. <!DOCTYPE html>
  2. <html lang="en">
  3. <head>
  4.     <meta charset="UTF-8">
  5.     <meta name="viewport" content="width=device-width, initial-scale=1.0">
  6.     <title>Document</title>
  7. </head>
  8. <body>
  9.     <script>
  10.         var str = "hello"; 
  11.         console.log(str.split()); // ["hello"]
  12.         console.log(str.split("")); // ["h", "e", "l", "l", "o"]
  13.         console.log(str.split("e")) // ["h", "llo"]
  14.     </script>
  15. </body>
  16. </html>

2.replace

replace可以替换字符

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        /* replace可以替换字符 */
        var str = "hello";
        console.log(str.replace("l","*"))//he*lo
    </script>
</body>
</html>

3.concat

字符串后添加字符串

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var str = "hello";
        var s = "world";
        console.log(str.concat(s));//htlloworld
    </script>
</body>
</html>

4.concat

字符串后添加字符串

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var str = "hello";
        var s = "world";
        console.log(str.concat(s));//htlloworld
    </script>
</body>
</html>

5.str[i];

slice(startIndex,endIndex)
substr(index,length)
subString(startIndex,endIndex)

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        /* 
        str[i];
        slice(startIndex,endIndex)
        substr(index,length)
        subString(startIndex,endIndex)
         */
        var str = "hello";

        console.log(str.substr(0,3));//hel
        console.log(str.substring(0,2))//he

    </script>
</body>
</html>

6.文字只显示两行，以省略号结尾

    display: -webkit-box;
    -webkit-box-orient: vertical;
    text-overflow: ellipsis;
    overflow: hidden;
    -webkit-line-clamp: 2;

例子：hello-olleh

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var str = "hello"
        var arr = str.split("");
        arr.reverse();
        var s = arr.join("");
        console.log(s);
    </script>
</body>
</html>

例子：[1,2,3,4,5,6,7,8,9]-[[1,2,3],[4,5,6],[7,8,9]]

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var arr = [1,2,3,4,5,6,7,8,9]
        //[[1,2,3],[4,5,6],[7,8,9]]
        /* 
        0  2
        3  5
        6  8
        length  3
        slice(startIndex,startIndex+3)
         */
        var sum =[];
        for(var i=0;i<arr.length;i=i+3){
             var item = arr.slice(i,i+3);
             sum.push(item);
        }
        console.log(sum)
    </script>
</body>
</html>

例子：[1,2,3,4,5,6]-[[1,2],[3,4],[5,6]]

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var sum = [];
        var arr = [1,2,3,4,5,6];
        for(i=0;i<arr.length;i+=2){
            var str = arr.slice(i,i+2);
            sum.push(str);
        }
        console.log(sum)
    </script>
</body>
</html>